JP2016081365A - Electronic device and control method of the same, control program thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently attain various kinds of functions in instruments having a real time OS installed, and to realize more power consumption.SOLUTION: An electronic device has: an oscillator 110 that generates a system clock signal; an oscillator 150 that generates an RTC clock signal (RTC) lower in frequency than the system clock signal, and is smaller in power consumption than the oscillator 110; a CPU 130 that has a real time OS installed; and function units 140 and 145. In the real time OS, periodically kernel ia booted to: operate a task execution state in the CPU 130 or an RTOS signal generation circuit generating an interruption signal for determining operational states of the function units 140 and 145 on the basis of the RTC clock signal to be output from the oscillator 150; and control a halt of a generation operation of the system clock signal in the oscillator 110 on the basis of the interruption signal and the task execution state in the CPU 130.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electronic device equipped with a real-time operating system, a control method thereof, and a control program.

  In recent years, various products (referred to as “wearable devices” for convenience) that can be worn on the human body to record and analyze various data during exercise such as running, cycling, swimming, trekking, and daily life. Developed and marketed. Portable information devices such as mobile phones, smart phones (high-function mobile phones), and tablet terminals are also widely used. Such devices are generally driven by power supplied from a battery power source, and various functions are realized by executing predetermined application programs in the arithmetic processing unit.

  On the other hand, the wearable devices and portable information devices described above have been improved in functionality in recent years by mounting various sensors and communication functions. As an operating system that solves the increase and complexity of processing operations due to the high functionality of such devices, a real-time operating system (RTOS; hereinafter referred to as “real-time OS”) is a multitasking operating system having real-time processing capability. For short). In a device equipped with a real-time OS, in order to manage tasks for realizing various functions, the kernel is started by periodic timer interruption and processing is performed. In addition, in devices driven by a battery power source, in addition to the above-described enhancement of functionality, there is a demand for power saving for extending the driving time.

  As a technique for realizing power saving in a device equipped with a real-time OS, for example, Patent Document 1 discloses a real-time OS system that generates an interrupt for starting an arithmetic processing unit such as a CPU when there is no task to be executed. A method is disclosed in which the interrupt processing period of the timer is set to be long and the arithmetic processing unit is shifted to the low power mode.

JP 2009-220459 A

  In a device equipped with a real-time OS, in general, an interrupt timer for periodically starting a kernel of an arithmetic processing device generates an interrupt signal based on a system clock signal serving as a reference for controlling the device. Here, the system clock signal is usually a basic clock signal for operating an arithmetic processing unit, other functional units connected to the arithmetic processing unit, peripheral circuits, and the like. Since the interrupt signal of the real-time OS is generated based on the above, even if there is no execution task in the arithmetic processing unit or peripheral (functional unit for controlling peripheral circuits, etc.), the kernel is started periodically Therefore, it is necessary to operate the interrupt timer. Therefore, the system clock signal cannot be stopped (that is, the oscillator itself that oscillates the system clock signal cannot be stopped), and the device is shifted to an operation mode with lower power consumption to further reduce power consumption. It had a problem that it was not possible to plan.

  Therefore, in view of the above-described problems, the present invention provides an electronic device that can realize various functions well in a device equipped with a real-time OS and can further save power, a control method thereof, and a control program. The purpose is to do.

The electronic device according to the present invention is
A first oscillator for generating a first clock signal;
A second oscillator for generating a second clock signal having a lower frequency than the first clock signal;
An arithmetic circuit unit that is equipped with a real-time operation system, operates based on the first clock signal, and executes a task;
A signal generation circuit for generating an interrupt signal based on the second clock signal;
A control circuit unit that controls stop of the operation of generating the first clock signal in the first oscillator based on the interrupt signal and the execution state of the task;
It is characterized by having.

An electronic device control method according to the present invention includes:
Generating a first clock signal by a first oscillator;
Generating a second clock signal having a frequency lower than that of the first clock signal by a second oscillator;
Operating based on the first clock signal to perform a task;
Generating an interrupt signal based on the second clock signal;
Based on the interrupt signal and the execution state of the task, the stop of the operation of generating the first clock signal in the first oscillator is controlled.

The control program according to the present invention is:
On the computer,
Generating a first clock signal by a first oscillator;
Generating a second clock signal having a frequency lower than that of the first clock signal by a second oscillator;
Operating based on the first clock signal to perform a task;
Generating an interrupt signal based on the second clock signal;
Stopping the generation operation of the first clock signal in the first oscillator is controlled based on the interrupt signal and the execution state of the task.

  According to the present invention, it is possible to achieve further power saving while successfully realizing various functions in a device equipped with a real-time OS.

It is a schematic block diagram which shows the some application example of the electronic device which concerns on this invention. It is a functional block diagram which shows one Embodiment of the electronic device which concerns on this invention. It is a flowchart which shows an example of the control method in the electronic device which concerns on one Embodiment. It is a conceptual diagram which shows the transition of the operation state of real-time OS of the electronic device which concerns on embodiment. It is a schematic block diagram which shows the structural example used as the comparison object of the electronic device which concerns on one Embodiment. It is a table | surface which shows an example of the experimental data for demonstrating the predominance of the effect in the electronic device which concerns on one Embodiment. It is a graph which shows an example of the experimental data for demonstrating the predominance of the effect in the electronic device which concerns on one Embodiment.

Hereinafter, an electronic device, a control method thereof, and a control program according to the present invention will be described in detail with reference to embodiments.
<Electronic equipment>
FIG. 1 is a schematic configuration diagram showing a plurality of application examples of an electronic apparatus according to the present invention. FIG. 2 is a functional block diagram showing an embodiment of an electronic apparatus according to the present invention.

  The present invention is applied to electronic devices having various sensors, communication functions, clock functions, and the like. Specifically, the electronic device is, for example, a sports watch 10 or a smart watch having a wristwatch-type or wristband-type appearance as shown in FIG. 1A, or an outdoor device such as mountaineering as shown in FIG. (For example, a GPS logger or a navigation terminal) 20, a smartphone 30 as shown in FIG. Hereinafter, for convenience of explanation, these devices are collectively referred to as “electronic device DVC”.

  As shown in FIG. 2, for example, the electronic device DVC according to the present embodiment includes an MCU (Micro Controller Unit) 100 having a form of an embedded microprocessor, a sensor unit 210 and a GPS receiving circuit 220 connected to the MCU 100, communication And peripheral circuits 230 such as a functional unit and a memory unit.

  The MCU 100 generally includes an oscillator 110, a PLL / frequency divider 120, a CPU (arithmetic circuit unit) 130, functional units 140 and 145, an oscillator 150, and a real-time OS signal generation circuit (hereinafter referred to as “RTOS signal”). Generation circuit ”160, a real-time clock signal generation unit (hereinafter referred to as“ RTC generation unit ”) 170, a control circuit 180, and a power supply unit 190.

  The oscillator (first oscillator) 110 includes a crystal oscillator that oscillates a system clock signal (first clock signal), and generates and outputs a system clock signal having a relatively high frequency of 16 MHz, for example. The PLL / frequency divider 120 divides the system clock signal output from the oscillator 110 by a PLL (phase locked loop) to generate an operation clock signal having a predetermined frequency, and the CPU 130 and sensor The data is supplied to the functional unit 140 to which the unit 210 is connected, the functional unit 145 to which the peripheral circuit 230 is connected, and the like. The oscillator 110 is controlled to stop and start the generation operation of the system clock signal based on a control signal output from the control circuit 180 described later.

  The CPU (arithmetic circuit unit) 130 executes various tasks by executing a predetermined application program based on an operation clock signal generated by the oscillator 110 and the PLL / frequency divider 120. Thereby, the CPU 130 performs various operations such as sensing operations of various sensors in the sensor unit 210, operations for acquiring position information and time information in the GPS receiving circuit 220, transmission / reception and input / output of various data and signals in the peripheral circuit 230, and the like. To control. The CPU 130 is equipped with a real-time OS, and based on an interrupt signal periodically output from an RTOS signal generation circuit 160, which will be described later, starts the kernel of the real-time OS at a predetermined cycle and executes various task execution states. And managing the operating states of the function units 140 and 145. Then, the CPU 130 controls the operation mode of the MCU 100 to one of the RUN mode, the SLEEP mode, and the STOP mode based on the interrupt signal, the task execution state, and the operation states of the function units 140 and 145. The operation state of the MCU 100 will be described later in detail.

The function units 140 and 145 are interface function units for controlling a sensor unit 210 and a peripheral circuit 230, which will be described later, connected to the MCU 100, and are operation clock signals generated by the oscillator 110 and the PLL / frequency divider 120. Based on the above, various data and signals are transmitted / received to / from the sensor unit 210 and the peripheral circuit 230 according to a predetermined communication standard. Here, the function unit 140 is connected to the sensor unit 210 via an interface of a synchronous serial communication standard such as I ² C (Inter-Integrated Circuit), for example, so that sensor data and the like are synchronized with various sensors. Send and receive. The function unit 145 transmits and receives predetermined data and signals by connecting to the peripheral circuit 230 via an interface of a serial communication standard such as SPI (Serial Peripheral Interface). Note that the communication standard applied to the functional units 140 and 145 is not limited to the above I ² C and SPI, but applies a known communication standard such as USB (Universal Serial Bus), for example. Also good.

  The CPU 130 and the functional units 140 and 145 described above are provided with switches SWa, SWb, and SWc for controlling the supply state of the operation clock signal generated by the oscillator 110 and the PLL / frequency divider 120, respectively. Yes. These switches SWa, SWb, and SWc are controlled to be on (clock signal supply) and off (clock signal cutoff) by the CPU 130 based on the task execution state and the operation states of the function units 140 and 145.

  The oscillator (second oscillator) 150 generates a real-time clock signal (RTC; second clock signal) for realizing a clock function (not shown) provided in the reference clock of the MCU 100 and the electronic device DVC. For example, a clock signal having a relatively low frequency of 32.768 KHz, for example, is generated and frequency-divided and supplied to the RTOS signal generation circuit 160 and the RTC generation unit 170 at all times. Here, since the reference clock signal generated by the oscillator 150 has a lower frequency than the system clock signal, the power consumption of the oscillator 150 is smaller (lower) than the power consumption of the oscillator 110.

  The RTOS signal generation circuit 160 generates and outputs an interrupt signal for periodically starting the real-time OS kernel based on the reference clock signal output from the oscillator 150. Thereby, the CPU 130 starts the kernel of the real-time OS at a predetermined cycle (for example, 512 Hz), and manages the execution state of various tasks and the operation states of the function units 140 and 145. Further, based on the interrupt signal, the operation state of the oscillator 110 is controlled by the control circuit 180 described later.

  The RTC generation unit 170 generates a real-time clock signal that is a reference clock of the MCU 100 based on the reference clock signal output from the oscillator 150. When the electronic device DVC is provided with a clock function, the clock operation and the time display are performed based on the real-time clock signal. Further, the RTC generation unit 170 may perform time correction based on time information included in a GPS signal received by a GPS receiving circuit 220 described later.

  The control circuit (control circuit unit) 180 is an oscillator 110 that oscillates a system clock signal based on the interrupt signal output from the RTOS signal generation circuit 160, the task execution state, and the operation states of the function units 140 and 145. Is controlled (system clock signal generation operation stop and start). In FIG. 2, the control circuit 180 is described as an independent configuration, but it may be provided inside the CPU 130, or an equivalent function is realized by a predetermined program (software). May be.

  The power supply unit 190 is provided, for example, inside the MCU 100 and supplies driving power to each component of the MCU 100. When the electronic device DVC is a portable device, the power supply unit 190 supplies power using a primary battery such as a commercially available button-type battery or a secondary battery such as a lithium ion battery as a power source. In addition to the primary battery and secondary battery described above, the power supply unit 190 can be used alone or in combination with a power source using energy harvesting technology that generates power using energy such as vibration, light, heat, and electromagnetic waves. And may be applied. 2 shows a configuration in which the power supply unit 190 is provided inside the MCU 100, it may be provided outside the MCU 100.

The sensor unit 210 includes, for example, an acceleration sensor 212, a magnetic sensor 214, an atmospheric pressure sensor 216, and the like, and is connected to the functional unit 140 via a communication standard interface such as I ² C. Each sensor of the sensor unit 210 transmits and receives the acquired sensor data and various signals to and from the MCU 100 via the function unit 140. Here, when the electronic device DVC according to the present embodiment is applied to an exercise support apparatus such as a running watch, the sensor unit 210 performs various physical or biological data (sensor data) related to the user's exercise state. It functions as sensor means for acquiring. The sensor unit 210 is not limited to each of the above sensors, but in addition to the above sensors, or instead of the above sensors, an angular velocity sensor (gyro sensor), a heart rate sensor, a pulse sensor, temperature and humidity You may provide various sensors according to the use application etc. of electronic devices DVC, such as a sensor.

  The GPS receiving circuit 220 receives radio waves from a plurality of GPS satellites constituting a GPS (Global Positioning System) via a GPS antenna (not shown), thereby receiving GPS signals from the GPS satellites. The geographical location information included in the is acquired and output as positioning data. The GPS receiving circuit 220 acquires time information included in the GPS signal and outputs the time information to the RTC generation unit 170 of the MCU 100. Thereby, time correction in the RTC 170 is performed.

  The peripheral circuit 230 includes a communication function unit, a memory unit, an output unit including a display unit (all of which are not shown), and is connected to the function unit 145 via an interface of a communication standard such as SPI. The peripheral circuit 230 transmits and receives various data and signals to and from the MCU 100 via the function unit 145.

(action mode)
Next, an operation mode of the MCU 100 having the above-described configuration will be described.
The MCU 100 sets the operation mode to one of the RUN mode, the SLEEP mode, and the STOP mode based on the interrupt signal output from the RTOS signal generation circuit 160, the task execution state, and the operation states of the function units 140 and 145. Switch and operate. Here, in this embodiment, the reference clock signal generation operation in the oscillator 150 is continued in any of the RUN mode, SLEEP mode, and STOP mode, and the RTOS signal generation circuit 160 and the RTC generation unit 170 The reference clock signal is always supplied.

  The RUN mode (first operation mode) is a state in which any task is executed in the CPU 130 (corresponding to an “execution state” in FIG. 4 described later), or a state in which execution of any task is prepared (described later). Corresponds to the “executable state” in FIG. 4), and is an operation mode in which the CPU 130 and the functional units 140 and 145 shown in FIG. 2 can be executed according to a predetermined program. In this RUN mode, the switches SWa to SWc are kept on, and the supply of the operation clock signal to the CPU 130 and the function units 140 and 145 is continued.

  In addition, the SLEEP mode (second operation mode) has no task executed by the CPU 130 (a state in which all tasks are in “waiting state” or “pause state” in FIG. 4 described later), and the functional unit 140. 145, the operation of transmitting and receiving various data and signals to and from the sensor unit 210 and the peripheral circuit 230 connected at 145 is maintained. In the SLEEP mode, the switch SWa is turned off, and the supply of the operation clock signal to the CPU 130 is shut off. Further, the switches SWb and SWc are kept on, and the supply of the operation clock signal to the functional units 140 and 145 is continued.

  Further, the STOP mode (third operation mode) has no task to be executed by the CPU 130 (the state in which all tasks are in “waiting state” or “pause state” in FIG. 4 described later), and the functional unit 140. 145, the data and signal transmission / reception operations with the sensor unit 210 and the peripheral circuit 230 are stopped. In this STOP mode, the generation operation of the system clock signal in the oscillator 110 is stopped, and the supply of the operation clock signal to the CPU 130 and the function units 140 and 145 is cut off. Here, the generation operation of the system clock signal in the oscillator 110 is controlled based on an interrupt signal or the like output from the RTOS signal generation circuit 160. When an interrupt signal is generated in the RTOS signal generation circuit 160 while the generation operation of the system clock signal is stopped, or when an interrupt is generated from the sensor unit 210 or the peripheral circuit 230 in the function units 140 and 145, Based on the control signal output from the control circuit 180, the generation operation of the system clock signal in the oscillator 110 is resumed. As a result, the operation clock signal is supplied to the CPU 130 and the function units 140 and 145, so that the task is executed by shifting from the STOP mode to the RUN mode, and data and signals with the sensor unit 210, the peripheral circuit 230, etc. The transmission / reception operation is performed.

  Here, in each of the above-described operation modes, the oscillator 110 performs a system clock signal generation operation, a predetermined task is executed in the CPU 130, and the functional units 140 and 145 communicate with the sensor unit 210, the peripheral circuit 230, and the like. The power consumption in the RUN mode in which data and signal transmission / reception operations are executed is maximized. Next, the power consumption in the SLEEP mode in which the supply of the operation clock signal to the CPU 130 is interrupted becomes the second largest, the system clock signal generation operation in the oscillator 110 is stopped, and the operation clock to the CPU 130 and the function units 140 and 145 is stopped. The power consumption in the STOP mode in which the signal supply is cut off is minimized.

<Control method of electronic equipment>
Next, a control method in the electronic apparatus according to the present embodiment will be described with reference to the drawings. Here, the control method of the electronic device shown in the following flowchart is realized by the CPU 130 having the above-described real-time OS executing processing according to a predetermined application program.

  FIG. 3 is a flowchart illustrating an example of a control method in the electronic device according to the present embodiment, and FIG. 4 is a conceptual diagram illustrating transition of the operation state of the real-time OS of the electronic device according to the present embodiment. Here, description will be made with reference to the configuration of the electronic device DVC (see FIG. 2) as appropriate.

  In the method for controlling the electronic device DVC according to the present embodiment, a series of processes as shown in the flowchart of FIG. 3 is executed, for example. First, when a user turns on a power switch (not shown), driving power is supplied from the power supply unit 190 to each component of the electronic device DVC, and the electronic device DVC is activated. As a result, the oscillator 110 of the MCU 100 is activated, the switches SWa, SWb, and SWc are controlled to be in an ON state, and an operation clock signal based on the system clock signal is supplied to the CPU 130 and the function units 140 and 145. The program is executed to perform an initial setting operation such as initialization of the peripheral circuit 230 including the sensor unit 210 and the memory unit connected to the function units 140 and 145 (step S102). The CPU 130 executes a predetermined task based on the application program, performs sensing operation in the sensor unit 210, operation for acquiring position information and time information in the GPS receiving circuit 220, and transmission and reception of various data and signals in the peripheral circuit 230. Execute various operations such as input and output. That is, the MCU 100 operates in the RUN mode in which a predetermined task is in an execution state or an executable state.

  Next, the CPU 130 monitors whether there is a timer interrupt during the execution of the task in the RUN mode (step S104). Here, in the present embodiment, an interrupt signal is generated by the RTOS signal generation circuit 160 based on the reference clock signal output from the oscillator 150 for generating a real-time clock signal, and is periodically output. The In step S104, when there is a timer interrupt (that is, when an interrupt signal is output from the RTOS signal generation circuit 160), the CPU 130 activates the kernel of the real-time OS at a predetermined cycle when receiving the interrupt signal. Then, operations for managing the execution states of various tasks and the operation states of the function units 140 and 145 are executed.

  Then, when the kernel of the real-time OS is activated, the CPU 130 determines whether there is an executable task (step S106). If there is a task in the executable state, the CPU 130 dispatches the task with the highest priority among the tasks, shifts to the execution state, and executes a predetermined process (step S108). Thereafter, the process returns to step S104, and whenever a timer interrupt occurs, the real-time OS kernel is activated and the same processing operation is repeated.

  On the other hand, if there is no task in an executable state in step S106, the CPU 130 determines whether or not there are functional units 140 and 145 that are in an operating state, that is, in operation (step S110). That is, the CPU 130 determines whether or not an operation of transmitting / receiving various data and signals to / from the sensor unit 210 and the peripheral circuit 230 connected to the function units 140 and 145 is performed. When there are functional units 140 and 145 in the operating state, the CPU 130 shifts the operation mode of the MCU 100 to the SLEEP mode (step S112). In other words, the switch SWa is controlled to be in an OFF state to cut off the supply of the operation clock signal to the CPU 130 and shift to an operation mode in which the supply of the operation clock signal to the functional unit in the operation state is continued. In the SLEEP mode, the MCU 100 is in a waiting state waiting for the task to shift to an executable state. Thereafter, returning to step S104, every time a timer interrupt occurs, the oscillator 110 is operated and the switch SWa is controlled to be turned on to start the CPU 130 and the real-time OS kernel is started to perform similar processing operations. repeat.

  On the other hand, in step S110, when there is no functional unit 140, 145 that is in the operating state, that is, in operation, the CPU 130 shifts the operation mode of the MCU 100 to the STOP mode (step S114). That is, the system clock generation operation in the oscillator 110 is stopped, and the operation mode is shifted to the operation mode in which the supply of the operation clock signal to the CPU 130 and the function units 140 and 145 is cut off. In the STOP mode, the MCU 100 is in a dormant state in which the oscillator 110, the CPU 130, and the function unit 140 related to the system clock signal are all suspended. Thereafter, returning to step S104, every time a timer interrupt occurs, the oscillator 110 is operated and the switch SWa is controlled to be turned on to start the CPU 130 and the real-time OS kernel is started to perform similar processing operations. repeat. Further, in the STOP mode, for example, when an external interrupt caused by a user operation or an interrupt from the RTC generation unit 170 occurs, the system clock signal generation operation in the oscillator 110 is restarted, and the CPU 130 and the function unit 140 are restarted. The operation clock signal is supplied to 145 to shift to the RUN mode.

  Although not shown in the flowchart shown in FIG. 3, the CPU 130 constantly monitors an input operation for interrupting or ending the processing operation or a change in the operating state during the execution of the series of processing operations described above. When the input operation or state change is detected, the processing operation is forcibly terminated. Specifically, the CPU 130 detects a user's operation of turning off the power switch, a decrease in the remaining battery level in the power supply unit 190, an abnormality in a function being executed or an application, and the like, and forcibly performs a series of processing operations. Stop and exit.

  As described above, in this embodiment, the kernel of the real-time OS is periodically started to determine the task execution state in the CPU 130 and the operation states of the function units 140 and 145, and based on the determination result, the electronic The MCU 100 of the device DVC is driven in an operation mode with appropriate power consumption. In the present embodiment, the RTOS signal generation circuit that generates an interrupt signal for periodically starting the kernel in the real-time OS is operated based on the system clock signal output from the oscillator 110 with high power consumption. Instead, the operation is based on an RTC clock signal (RTC) output from an oscillator 150 with low power consumption.

(Verification of effects)
Next, the effects of the electronic device according to the present embodiment and the control method thereof will be described in detail with reference to a comparative example.
FIG. 5 is a schematic block diagram illustrating a configuration example to be compared for explaining the superiority of the operational effects in the electronic device and the control method thereof according to the present embodiment. Here, about the structure equivalent to embodiment mentioned above, an equivalent code | symbol is attached | subjected and description is simplified.

  A configuration example (hereinafter referred to as “comparative example”) to be compared with the electronic apparatus according to the present embodiment is a PLL / minute based on a system clock signal oscillated in the oscillator 110 of the MCU 100P, for example, as shown in FIG. An operation clock signal is generated by the peripheral 120 and supplied to each of the CPU 130, the function units 140 and 145, and the RTOS signal generation circuit 160P. That is, for example, a SysTick timer circuit that operates based on the system clock signal is used as the RTOS signal generation circuit 160P for generating an interrupt signal for periodically starting the kernel of the real-time OS.

  Thus, in the MCU 100P of the comparative example, the RTOS signal generation circuit 160P that outputs an interrupt signal for starting the kernel of the real-time OS operates based on the system clock signal. Therefore, in the comparative example, when there is no execution task in the CPU 130 or the functional units 140 and 145, when the MCU 100P is shifted to the above-described STOP mode, the supply of the operation clock signal to the RTOS signal generation circuit 160P is also stopped. As a result, the CPU 130 cannot be activated periodically. In other words, in the comparative example, the generation operation of the system clock signal in the oscillator 110 cannot be stopped (cannot be shifted to the STOP mode), and the MCU 100P has two modes of the RUN mode and the SLEEP mode. It will be switched to operate. For this reason, it means that the power consumption in the oscillator 110 cannot be reduced.

  On the other hand, in the MCU 100 described in the above-described embodiment, the RTOS signal generation circuit 160 sets the real-time OS kernel based on the reference clock signal output from the oscillator 150 for generating the real-time clock signal. Generate and output an interrupt signal to activate. Thereby, in this embodiment, it is possible to shift to the STOP mode in which the generation operation of the system clock signal in the oscillator 110 is stopped, and the MCU 100 operates by switching between three modes of the RUN mode, the SLEEP mode, and the STOP mode. be able to. Here, since the frequency of the reference clock signal generated by the oscillator 150 is sufficiently lower than that of the system clock signal, the oscillator 150 can be driven with lower power consumption than that of the oscillator 110. Therefore, in an electronic device equipped with a real-time OS, various functions can be satisfactorily realized, power consumption can be further reduced, and the driving time of the device can be extended.

  FIG. 6 is a table showing an example of experimental data for explaining the superiority of the operational effects in the electronic device according to the present embodiment. FIG. 7 shows the superiority of the operational effects in the electronic device according to the present embodiment. It is a graph which shows an example of the experimental data for demonstrating.

FIG. 6 shows the results of measuring the current consumption in the configuration according to the present embodiment (see FIG. 2) and the configuration of the comparative example (see FIG. 5) under the following conditions.
(Measurement condition)
(1) Oscillator 110 oscillates system clock signal at 16 MHz (2) Data acquisition at acceleration sensor 212 at 50 Hz sampling frequency (3) Data acquisition at magnetic sensor 214 at 16 Hz sampling frequency (4) Data acquisition at 10 Hz at atmospheric pressure sensor 216 Data acquisition at sampling frequency (5) GPS receiver circuit 220 is not operating

  Specifically, as shown in FIG. 6, in the configuration of the comparative example, the average value of the current flowing through the MCU 100 </ b> P (denoted as “MCU current” in the table) is 5.88 mA and flows to the output terminal of the power supply unit 190. The average value of the current (expressed as “battery end current” in the table) was 7.87 mA. In contrast, in the configuration according to the present embodiment, the average value (MCU current) of the current flowing through the MCU 100 is 3.17 mA, and the average value of the current (battery end current) flowing through the output terminal of the power supply unit 190 is 5. It was 0.63 mA. As a result, the current reduction rate in the present embodiment relative to the comparative example is that the current flowing through the MCU 100 (MCU current) reaches 46%, the current flowing through the output end of the power supply unit 190 (battery end current) reaches 28%, and consumption It has been found that the current can be greatly reduced.

Further, FIG. 7 schematically shows changes in current value in each operation mode in the present embodiment and the comparative example.
Specifically, in the configuration of the comparative example, since the RTOS signal generation circuit 160P operates based on the system clock signal, the MCU 100P shifts the operation mode to the STOP mode as shown in FIG. 7A. Therefore, the operation is switched between the RUN mode and the SLEEP mode which consumes less current (5 mA) than the RUN mode.

  On the other hand, in the configuration of the present embodiment, since the RTOS signal generation circuit 160 operates based on the reference clock signal for generating the real-time clock signal, the MCU 100 operates as shown in FIG. The operation is switched between three modes: a RUN mode, a SLEEP mode with a current consumption of 5 mA, and a STOP mode with a current consumption still smaller than that of the SLEEP mode (400 μA). In particular, in the present embodiment, the MCU 100 is shifted to the STOP mode as shown in FIG. 7C during a period in which there is no execution task in the CPU 130 or the functional units 140 and 145 and no timer interrupt has occurred. As a result, the current consumption can be significantly reduced compared to the comparative example (see the hatched portion in the figure).

  In the above-described embodiment, the case where the stop and start of the generation operation of the system clock signal in the oscillator 110 is controlled based on the control signal output from the control circuit 180 in the STOP mode has been described. Is not limited to this. For example, based on a control signal output from the control circuit 180, by controlling the cutoff and supply of driving power from the power supply unit 190 to the oscillator 110 and further to each component operating based on the system clock signal The system 110 may be configured to stop and start the generation operation of the system clock signal in the oscillator 110 and to control the operation state of each component.

  Moreover, in this embodiment, the structure which acquires a positional information and time information with the GPS receiving circuit 220 connected to MCU100 was shown. Here, the power consumption in the GPS receiving circuit 220 is relatively large (for example, 20 to 25 mA) among the configurations provided in the electronic device DVC. Therefore, from the viewpoint of power saving of the electronic device DVC, it is desirable to control the GPS receiving circuit 220 so as not to operate as much as possible by intermittently operating it. Specifically, for example, the GPS reception circuit 220 is operated only for 1 minute out of 10 minutes, and the GPS reception circuit 220 is stopped for the remaining 9 minutes. In this case, since position information and time information cannot be acquired during a period when the GPS receiving circuit 220 is not operating, dead using the acceleration sensor 212, the magnetic sensor 214, and the atmospheric pressure sensor 216 provided in the sensor unit 210. The current position may be calculated and interpolated by reckoning (dead reckoning navigation or autonomous navigation).

  In the present embodiment, the MCU 100 is configured such that the oscillators 110 and 150, the CPU 130, the functional units 140 and 145, the RTOS signal generation circuit 160, and the like are mounted on a single LSI. It is not limited to. For example, at least one of a component that operates based on the system clock signal output from the oscillator 110, a component that operates based on the RTC output from the oscillator 150, and a component including the power supply unit 190. One may have a configuration mounted on separate chips. Thereby, the design freedom of an electronic device can be improved.

As mentioned above, although some embodiment of this invention was described, this invention is not limited to embodiment mentioned above, It includes the invention described in the claim, and its equivalent range.
Hereinafter, the invention described in the scope of claims of the present application will be appended.

(Appendix)
[1]
A first oscillator for generating a first clock signal;
A second oscillator for generating a second clock signal having a lower frequency than the first clock signal;
An arithmetic circuit unit that is equipped with a real-time operation system, operates based on the first clock signal, and executes a task;
A signal generation circuit for generating an interrupt signal based on the second clock signal;
A control circuit unit that controls stop of the operation of generating the first clock signal in the first oscillator based on the interrupt signal and the execution state of the task;
An electronic device comprising:

[2]
A functional unit that operates based on the first clock signal;
The electronic device according to [1], wherein the arithmetic circuit unit monitors an execution state of the task and an operation state of the functional unit based on the interrupt signal.

[3]
The electronic device according to [2], wherein the arithmetic circuit unit switches an operation mode of the electronic device according to an execution state of the task and an operation state of the function unit.

[4]
The operation mode includes a first operation mode in which the task to be executed is present and the function unit is operating, and an operation state in which the task is not performed and the function unit is operating. The electronic device according to [3], including a second operation mode and a third operation mode in which the task to be executed is not performed and the functional unit is not operating. machine.

[5]
The electronic device according to [4], wherein the control circuit unit stops the operation of generating the first clock signal in the first oscillator in the third operation mode.

[6]
[4] The electronic device according to [4], further comprising a switch that controls a supply state of the first clock signal to the arithmetic circuit unit and the functional unit according to the operation mode.

[7]
The electronic device according to [6], wherein the switch is controlled to stop supplying the first clock signal to the arithmetic circuit unit in the second operation mode.

[8]
The electronic device according to any one of [1] to [7], wherein the electronic device has a clock function and performs a clock operation based on the second clock signal.

[9]
Generating a first clock signal by a first oscillator;
Generating a second clock signal having a frequency lower than that of the first clock signal by a second oscillator;
Operating based on the first clock signal to perform a task;
Generating an interrupt signal based on the second clock signal;
A method for controlling an electronic device, comprising: controlling stop of the operation of generating the first clock signal in the first oscillator based on the interrupt signal and an execution state of the task.

[10]
On the computer,
Generating a first clock signal by a first oscillator;
Generating a second clock signal having a frequency lower than that of the first clock signal by a second oscillator;
Operating based on the first clock signal to perform a task;
Generating an interrupt signal based on the second clock signal;
A control program that controls stop of the operation of generating the first clock signal in the first oscillator based on the interrupt signal and the execution state of the task.

100 MCU
110, 150 oscillator 130 CPU
140, 145 Function unit 160 RTOS signal generation circuit 170 RTC generation unit 180 Control circuit 190 Power supply unit 210 Sensor unit 220 GPS reception circuit 230 Peripheral circuit DVC Electronic device

Claims (10)

A first oscillator for generating a first clock signal;
A second oscillator for generating a second clock signal having a lower frequency than the first clock signal;
An arithmetic circuit unit that is equipped with a real-time operation system, operates based on the first clock signal, and executes a task;
A signal generation circuit for generating an interrupt signal based on the second clock signal;
A control circuit unit that controls stop of the operation of generating the first clock signal in the first oscillator based on the interrupt signal and the execution state of the task;
An electronic device comprising: A functional unit that operates based on the first clock signal;
The electronic apparatus according to claim 1, wherein the arithmetic circuit unit monitors an execution state of the task and an operation state of the function unit based on the interrupt signal.   The electronic device according to claim 2, wherein the arithmetic circuit unit switches an operation mode of the electronic device according to an execution state of the task and an operation state of the function unit.   The operation mode includes a first operation mode in which the task to be executed is present and the function unit is operating, and an operation state in which the task is not performed and the function unit is operating. 4. The electronic device according to claim 3, further comprising: a second operation mode; and a third operation mode that is an operation state in which the task is not performed and the functional unit is not operating. machine.   The electronic apparatus according to claim 4, wherein the control circuit unit stops the operation of generating the first clock signal in the first oscillator in the third operation mode.   The electronic apparatus according to claim 4, further comprising a switch that controls a supply state of the first clock signal to the arithmetic circuit unit and the functional unit according to the operation mode.   The electronic device according to claim 6, wherein the switch is controlled to stop supplying the first clock signal to the arithmetic circuit unit in the second operation mode.   The electronic device according to claim 1, wherein the electronic device has a clock function and performs a clock operation based on the second clock signal. Generating a first clock signal by a first oscillator;
Generating a second clock signal having a frequency lower than that of the first clock signal by a second oscillator;
Operating based on the first clock signal to perform a task;
Generating an interrupt signal based on the second clock signal;
A method for controlling an electronic device, comprising: controlling stop of the operation of generating the first clock signal in the first oscillator based on the interrupt signal and an execution state of the task. On the computer,
Generating a first clock signal by a first oscillator;
Generating a second clock signal having a frequency lower than that of the first clock signal by a second oscillator;
Operating based on the first clock signal to perform a task;
Generating an interrupt signal based on the second clock signal;
A control program that controls stop of the operation of generating the first clock signal in the first oscillator based on the interrupt signal and the execution state of the task.

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